The Flood Super Cell[1], often abbreviated as the FSC, is an undifferentiated cell type that serves as the basis of all Flood biomass.
Biology
The Flood super cell can be described as a "thinking muscle" and closely resembles neurons or glial cells in structure.[2] The Flood have demonstrated on numerous occasions that they have the ability to arrange these FSC's to mimic any organ that may be necessary. Apparently, it is also capable of intelligent discourse with artificial intelligences, such as Mendicant Bias. The Flood Infection Form use their tendrils to place this cell into any living organism, turning them into the Flood.
History
The Gravemind was the entity that communicated with the Forerunner AI 032 Mendicant Bias during the Forerunner-Flood War to convince it into rampancy and to turn it into a weapon against the Forerunners, using the Flood super cell to initiate communications. For a time, Mendicant Bias took faith in the Gravemind, believing the Forerunners were obstinate, unyielding, and blocking evolution's progress in the galaxy. However, after the firing of the Halo Array, Mendicant Bias realized how far he had fallen and denounced the Flood, pleading for the forgiveness of the Reclaimer in order to redeem his actions against his long-lost creators.